Association between the CHRM2 gene and intelligence in a sample of 304 Dutch families.

The CHRM2 gene is thought to be involved in neuronal excitability, synaptic plasticity and feedback regulation of acetylcholine release and has previously been implicated in higher cognitive processing. In a sample of 667 individuals from 304 families, we genotyped three singlenucleotide polymorphisms (SNPs) in the CHRM2 gene on 7q31–35. From all individuals, standardized intelligence measures were available. Using a test of within-family association, which controls for the possible effects of population stratification, a highly significant association was found between the CHRM2 gene and intelligence. The strongest association was between rs324650 and performance IQ (PIQ), where the T allele was associated with an increase of 4.6 PIQ points. In parallel with a large familybased association, we observed an attenuated – although still significant – population-based association, illustrating that population stratification may decrease our chances of detecting allele–trait associations. Such a mechanism has been predicted earlier, and this article is one of the first to empirically show that family-based association methods are not only needed to guard against false positives, but are also invaluable in guarding against false negatives

The Play Behaviours of Roma Children in Transylvania

The Roma children of Transylvania are probably the most materially deprived in Europe. They often live in one-room shacks made from wood and mud, with no running water, no sanitation, and sometimes no heating. Many rely on charity for their food and medicines. But, are they play deprived? This paper summarises an observational study of the play behaviours of children in a small Roma village. It highlights the striking contrast between the abject poverty that characterises their lives and the general happiness of the children. These children live their limited lives to the full. They ‘play everywhere and with everything’, but not in the generally accepted sense of that phrase. The usual niceties of privacy, personal possessions and property boundaries are irrelevant here. Their play is rich in imagination and creativity; it is living proof of Nicholson’s theory of loose parts

An Ancient Duplication of Exon 5 in the Snap25 Gene Is Required for Complex Neuronal Development/Function

Alternative splicing is an evolutionary innovation to create functionally diverse proteins from a limited number of genes. SNAP-25 plays a central role in neuroexocytosis by bridging synaptic vesicles to the plasma membrane during regulated exocytosis. The SNAP-25 polypeptide is encoded by a single copy gene, but in higher vertebrates a duplication of exon 5 has resulted in two mutually exclusive splice variants, SNAP-25a and SNAP-25b. To address a potential physiological difference between the two SNAP-25 proteins, we generated gene targeted SNAP-25b deficient mouse mutants by replacing the SNAP-25b specific exon with a second SNAP-25a equivalent. Elimination of SNAP-25b expression resulted in developmental defects, spontaneous seizures, and impaired short-term synaptic plasticity. In adult mutants, morphological changes in hippocampus and drastically altered neuropeptide expression were accompanied by severe impairment of spatial learning. We conclude that the ancient exon duplication in the Snap25 gene provides additional SNAP-25-function required for complex neuronal processes in higher eukaryotes

Permian high-temperature metamorphism in the Western Alps (NW Italy)

During the late Palaeozoic, lithospheric thinning in part of the Alpine realm caused high-temperature low-to-medium pressure metamorphism and partial melting in the lower crust. Permian metamorphism and magmatism has extensively been recorded and dated in the Central, Eastern, and Southern Alps. However, Permian metamorphic ages in the Western Alps so far are constrained by very few and sparsely distributed data. The present study fills this gap. We present U/Pb ages of metamorphic zircon from several Adria-derived continental units now situated in the Western Alps, defining a range between 286 and 266 Ma. Trace element thermometry yields temperatures of 580-890°C from Ti-in-zircon and 630-850°C from Zr-in-rutile for Permian metamorphic rims. These temperature estimates, together with preserved mineral assemblages (garnet-prismatic sillimanite-biotite-plagioclase-quartz-K-feldspar-rutile), define pervasive upper-amphibolite to granulite facies conditions for Permian metamorphism. U/Pb ages from this study are similar to Permian ages reported for the Ivrea Zone in the Southern Alps and Austroalpine units in the Central and Eastern Alps. Regional comparison across the former Adriatic and European margin reveals a complex pattern of ages reported from late Palaeozoic magmatic and metamorphic rocks (and relics thereof): two late Variscan age groups (~330 and ~300 Ma) are followed seamlessly by a broad range of Permian ages (300-250 Ma). The former are associated with late-orogenic collapse; in samples from this study these are weakly represented. Clearly, dominant is the Permian group, which is related to crustal thinning, hinting to a possible initiation of continental rifting along a passive margin

Morphological docking of secretory vesicles

Calcium-dependent secretion of neurotransmitters and hormones is essential for brain function and neuroendocrine-signaling. Prior to exocytosis, neurotransmitter-containing vesicles dock to the target membrane. In electron micrographs of neurons and neuroendocrine cells, like chromaffin cells many synaptic vesicles (SVs) and large dense-core vesicles (LDCVs) are docked. For many years the molecular identity of the morphologically docked state was unknown. Recently, we resolved the minimal docking machinery in adrenal medullary chromaffin cells using embryonic mouse model systems together with electron-microscopic analyses and also found that docking is controlled by the sub-membrane filamentous (F-)actin. Currently it is unclear if the same docking machinery operates in synapses. Here, I will review our docking assay that led to the identification of the LDCV docking machinery in chromaffin cells and also discuss whether identical docking proteins are required for SV docking in synapses

Inelastic scattering of light by magnetic excitons in the pseudo Ising antiferromagnets K2CoF4 and Rb2CoF4

In addition to previously reported phonon Raman scattering, we have observed inelastic light scattering by magnetic excitons in K2CoF 4 and Rb2CoF4 ; the polarized spectra have been studied at low temperatures under an applied magnetic field up to about 5 teslas. The results are interpreted on the basis of a multilevel propagating exciton model deduced from a Hamiltonian including the single ion spin-orbit coupling, the low symmetry crystal field and a nearest neighbours Heisenberg exchange interaction, acting in the 4Γ+4 (Oh) ground state of Co 2+. From the lowest exciton study we derive a value of the tetragonal crystal field Δ (— 425 cm-1 and — 635 cm -1, respectively in K2CoF4 and Rb2CoF 4) and of the isotropic exchange parameter J ( — 11.55 cm-1 and — 9.65 cm-1, respectively in K 2CoF4 and Rb2CoF4). The remaining features of the spectra, which include one and two exciton scattering, are partly interpreted using the above model with these values. The derived J values are close to previous determinations in KCoF3 and RbCoF 3, as expected. The Ising character, which is caused by the low symmetry crystal field, is found to be less marked when evaluated from the magnon dispersion results than it was indicated by previous magnetic measurements, and this has been confirmed by recent inelastic neutron scattering data in Rb2CoF 4.Outre l'effet Raman dû aux phonons, antérieurement signalé, nous observons la diffusion inélastique de la lumière liée aux excitons magnétiques dans K2CoF4 et Rb2CoF4 ; les spectres polarisés ont été étudiés à basse température en présence d'un champ magnétique pouvant atteindre 5 teslas environ. Nous interprétons les résultats au moyen d'un modèle multi-excitonique déduit d'un Hamiltonien tenant compte du couplage spin-orbite, du champ cristallin de basse symétrie et d'une interaction d'échange de type Heisenberg, perturbant l'état fondamental 4Γ+4 (Oh) des ions Co2+. De l'étude de l'exciton de plus basse énergie, nous déduisons la valeur du champ cristallin quadratique Δ (— 425 cm-1 et — 635 cm -1, respectivement pour K2CoF4 et Rb2CoF 4) ainsi que celle du paramètre d'échange isotrope J (— 11,55 cm-1 et — 9,65 cm-1, respectivement pour K2CoF4 et Rb2CoF4). Le reste du spectre, qui contient des contributions à la diffusion par un et par deux excitons, est partiellement interprété, grâce au modèle ci-dessus décrit, pour les valeurs ainsi déterminées des paramètres Δ et J, dont il dépend. Les valeurs de J sont voisines de celles qui ont été antérieurement trouvées pour KCoF 3 et RbCoF3, comme prévu. Le comportement de type Ising, qui provient du champ cristallin de basse symétrie apparaît moins marqué lorsqu'on l'évalue à partir de la courbe de dispersion des magnons que ne le laissaient prévoir d'anciennes mesures magnétiques, résultat confirmé par une récente étude de diffusion inélastique de neutrons dans Rb2CoF4